$subtotal = price_format_decimal($this->cart_model->get_sess_cart_total()->subtotal);
        $cart_items = $this->cart_model->get_sess_cart_items();
        $user = user();
        $options = $this->initialize_iyzico();
        $buyer_id = "guest_" . uniqid();
        if (auth_check()) {
            $buyer_id = user()->id;
        }
        $ip = $_SERVER['REMOTE_ADDR'];
        $country_name = "Turkey";
        if(user()->country_id == 222)
        {
            $currency = 'TRY';
        }else{
            $currency = 'USD';
        }
        # create request class
        $request = new \Iyzipay\Request\CreatePaymentRequest();
        $request->setLocale(\Iyzipay\Model\Locale::EN);
        $request->setConversationId("123456789");
        $request->setPrice($subtotal);
        $request->setPaidPrice($subtotal);
        $request->setCurrency(\Iyzipay\Model\Currency::USD);
        $request->setInstallment(1);
        $request->setBasketId("B678321234");
        $request->setPaymentChannel(\Iyzipay\Model\PaymentChannel::WEB);
        $request->setPaymentGroup(\Iyzipay\Model\PaymentGroup::PRODUCT);
        $request->setCallbackUrl("https://3dstock.org/cart_controller/iyzico_payment_result");

        //credit card info
        $paymentCard = new \Iyzipay\Model\PaymentCard();
        $paymentCard->setCardHolderName($this->input->post('name', true));
        $paymentCard->setCardNumber($this->input->post('card_number', true));
        $paymentCard->setExpireMonth($this->input->post('month', true));
        $paymentCard->setExpireYear($this->input->post('year', true));
        $paymentCard->setCvc($this->input->post('cvc', true));
        $paymentCard->setRegisterCard(0);
        $request->setPaymentCard($paymentCard);

        $buyer = new \Iyzipay\Model\Buyer();
        $buyer->setId($user->id);
        $buyer->setName($user->username);
        $buyer->setSurname($user->username);
        //$buyer->setGsmNumber("+905350000000");
        $buyer->setEmail($user->email);
        $buyer->setIdentityNumber("12454670166");
        //$buyer->setLastLoginDate("2015-10-05 12:43:35");
        //$buyer->setRegistrationDate("2013-04-21 15:12:09");
        $buyer->setRegistrationAddress($user->address);
        $buyer->setIp($ip);
        $buyer->setCity($this->location_model->get_state(user()->state_id)->name);
        $buyer->setCountry($this->location_model->get_country(user()->country_id)->name);
        $buyer->setZipCode($user->zip_code);
        $request->setBuyer($buyer);

        $shippingAddress = new \Iyzipay\Model\Address();
        $shippingAddress->setContactName($user->username);
        $shippingAddress->setCity($this->location_model->get_state(user()->state_id)->name);
        $shippingAddress->setCountry($this->location_model->get_country(user()->country_id)->name);
        $shippingAddress->setAddress($user->address);
        $shippingAddress->setZipCode($user->zip_code);
        $request->setShippingAddress($shippingAddress);

        $billingAddress = new \Iyzipay\Model\Address();
        $billingAddress->setContactName($user->username);
        $billingAddress->setCity($this->location_model->get_state(user()->state_id)->name);
        $billingAddress->setCountry($this->location_model->get_country(user()->country_id)->name);
        $billingAddress->setAddress($user->address);
        $billingAddress->setZipCode($user->zip_code);
        $request->setBillingAddress($billingAddress);

        $basketItems = array();
        $count = 0;
        if (!empty($cart_items)):
			foreach ($cart_items as $cart_item):
				$product = get_available_product($cart_item->product_id);
				$vendor = get_user($product->user_id);
                //echo $vendor->SubMerchantKey.'<br>';
                //echo $vendor->username.'<br>';
				if (!empty($product)) {
					$BasketItem = new \Iyzipay\Model\BasketItem();
					$BasketItem->setId('8978797987');
					$BasketItem->setName('deneme');
					$BasketItem->setCategory1(trans("order"));
					$BasketItem->setItemType(\Iyzipay\Model\BasketItemType::VIRTUAL);
					$BasketItem->setPrice(price_format_decimal($cart_item->total_price));
					$BasketItem->setSubMerchantKey($vendor->SubMerchantKey);
					$BasketItem->setSubMerchantPrice(price_format_decimal($cart_item->total_price));
					$basketItems[$count] = $BasketItem;
					$count++;
				}
			endforeach;
		endif;
		$request->setBasketItems($basketItems);

        # make request
        //$payment = \Iyzipay\Model\Payment::create($request, $options);
        $payment = \Iyzipay\Model\ThreedsInitialize::create($request, $options);

        echo '<pre>';
        print_r($payment);
        echo '</pre>';